conf: Allow specifying only the slot number for hotpluggable memory

Simplify handling of the 'dimm' address element by allowing to specify
the slot number only. This will allow libvirt to allocate slot numbers
before starting qemu.

src/conf/domain_conf.c

@@ -5007,7 +5007,8 @@ virDomainDeviceInfoFormat(virBufferPtr buf,
 
     case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DIMM:
         virBufferAsprintf(buf, " slot='%u'", info->addr.dimm.slot);
-        virBufferAsprintf(buf, " base='0x%llx'", info->addr.dimm.base);
+        if (info->addr.dimm.base)
+            virBufferAsprintf(buf, " base='0x%llx'", info->addr.dimm.base);
 
         break;
 
@@ -5408,14 +5409,15 @@ virDomainDeviceDimmAddressParseXML(xmlNodePtr node,
     }
     VIR_FREE(tmp);
 
-    if (!(tmp = virXMLPropString(node, "base")) ||
-        virStrToLong_ullp(tmp, NULL, 16, &addr->base) < 0) {
-        virReportError(VIR_ERR_XML_ERROR,
-                       _("invalid or missing dimm base address '%s'"),
-                       NULLSTR(tmp));
-        goto cleanup;
+    if ((tmp = virXMLPropString(node, "base"))) {
+        if (virStrToLong_ullp(tmp, NULL, 16, &addr->base) < 0) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("invalid dimm base address '%s'"), tmp);
+            goto cleanup;
+        }
+
+        VIR_FREE(tmp);
     }
-    VIR_FREE(tmp);
 
     ret = 0;
 

src/qemu/qemu_command.c

@@ -3497,7 +3497,8 @@ qemuBuildMemoryDeviceStr(virDomainMemoryDefPtr mem)
 
         if (mem->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DIMM) {
             virBufferAsprintf(&buf, ",slot=%d", mem->info.addr.dimm.slot);
-            virBufferAsprintf(&buf, ",addr=%llu", mem->info.addr.dimm.base);
+            if (mem->info.addr.dimm.base)
+                virBufferAsprintf(&buf, ",addr=%llu", mem->info.addr.dimm.base);
         }
 
         break;

tests/qemuxml2argvdata/qemuxml2argv-memory-hotplug-dimm-addr.args

@@ -15,6 +15,8 @@ QEMU_AUDIO_DRV=none \
 mem-path=/dev/hugepages2M/libvirt/qemu,size=536870912,host-nodes=1-3,\
 policy=bind \
 -device pc-dimm,node=0,memdev=memdimm0,id=dimm0,slot=0,addr=4294967296 \
+-object memory-backend-ram,id=memdimm1,size=536870912 \
+-device pc-dimm,node=0,memdev=memdimm1,id=dimm1,slot=2 \
 -uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
 -nographic \
 -nodefaults \

tests/qemuxml2argvdata/qemuxml2argv-memory-hotplug-dimm-addr.xml

@@ -2,8 +2,8 @@
   <name>QEMUGuest1</name>
   <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
   <maxMemory slots='16' unit='KiB'>1099511627776</maxMemory>
-  <memory unit='KiB'>743423</memory>
-  <currentMemory unit='KiB'>743423</currentMemory>
+  <memory unit='KiB'>7434230</memory>
+  <currentMemory unit='KiB'>7434230</currentMemory>
   <vcpu placement='static' cpuset='0-1'>2</vcpu>
   <os>
     <type arch='i686' machine='pc'>hvm</type>
@@ -41,5 +41,12 @@
       </target>
       <address type='dimm' slot='0' base='0x100000000'/>
     </memory>
+    <memory model='dimm'>
+      <target>
+        <size unit='KiB'>524287</size>
+        <node>0</node>
+      </target>
+      <address type='dimm' slot='2'/>
+    </memory>
   </devices>
 </domain>

tests/qemuxml2argvtest.c

@@ -2096,7 +2096,7 @@ mymain(void)
     DO_TEST("memory-hotplug-dimm", QEMU_CAPS_DEVICE_PC_DIMM, QEMU_CAPS_NUMA,
             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);
     DO_TEST("memory-hotplug-dimm-addr", QEMU_CAPS_DEVICE_PC_DIMM, QEMU_CAPS_NUMA,
-            QEMU_CAPS_OBJECT_MEMORY_FILE);
+            QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);
     DO_TEST("memory-hotplug-ppc64-nonuma", QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_PC_DIMM, QEMU_CAPS_NUMA,
             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);